This invention is directed to an improved metal frame for electronic hardware, and preferably to metal frames made of Fe and Zr-based bulk-solidifying amorphous alloys and bulk-solidifying amorphous alloy-composites.
A conventional electronic device can be functionally separated for convenience into two portions: an electronics portion, which provides the functional utility of the electronic device; and an external frame portion which provides physical protection to the electronics portion. To provide optimum protection, the frame physically encapsulates the working components (such as including one or more microprocessors, memory devices, storage devices) of the electronic device: such as a portable computer, personal data assistant (xe2x80x9cPDAxe2x80x9d), or cell-phone.
For example, in portable personal computers, commonly referred to as notebook computers, a housing formed from a top case and a bottom case is used to support and house a screen, a computer, and interface devices. Typically, the case also forms a mounting structure for fastening together the various components comprising the computer. The various components, including the logic board and disk drives, are attached to either the upper or lower half of the case by means of screws or other such fastening means. Electromagnetic Interference (xe2x80x9cEMIxe2x80x9d) protection is incorporated into the case by placing a sheet of shielding material inside both halves of the case or by surrounding the relevant components with a metal structure which isolates them from the environment. In constructing a typical notebook computer case, or any portable electronic device case, an effort is made to minimize overall weight while maximizing the device""s processing power, memory storage and shock resistance.
In an effort to achieve this end a number of design elements are utilized. First, to minimize the size of the electronic device the electronic components are miniaturized and lightweight thin panel displays are incorporated into devices. Secondly, the structure used to mount and isolate the various components of the computer from shock is kept to a minimum, and in fact, the housing typically has molded-in reinforcements, ribs, and mounting bosses along its molded inner face to which components are mounted. Typically, the various circuit boards within the notebook computer are directly mounted with fasteners to the molded-in bosses and ribs. Finally, to minimize the weight of the device most of the cases for such computers have been constructed from pieces of a light weight very stiff plastics or composite materials.
Although these methods for constructing portable computers are acceptable, they leave room for improvement. For example, from a material standpoint, although plastic and composites are light weight and easily processable into the complex shapes required for most electronics cases, the structural strength and durability available from a plastic or composite material is typically not as good as that obtainable from metal. In addition, a separate EMI protection layer must be interposed between the case and electronics when using a plastic or composite material instead of a metal.
However, the weight and cost penalty for fabricating the entire case from metal is usually too great for a portable electronic device, except in such specialty markets as the military. For example, attempts have been made to correct the strength and durability problems associated with plastic cases by forming a portable computer where the case is made from die-cast metal upper and lower halves. Although this creates a relatively strong and durable computer, it weighs too much for easy portability and the cost of such a computer is too high. Other manufactures have made various subassemblies from sheet metal but the resulting computer is not noticeably stronger. In addition, most conventional metals are very difficult to adequately shape.
Recently work has been conducted on magnesium alloys because of their relatively low density and high strength properties. However, such alloys have much poorer plastic working properties than conventional alloys, such as Al-based alloys. Accordingly, the magnesium alloys are usually provided as die-castings at present. However, magnesium alloy castings are still limited to relatively thick products, because it is extremely difficult to cast magnesium alloys into thin products. In addition, casting defects such as pores and inclusions such as oxides, which are inevitable in casting, may be contained in the magnesium alloy castings and appear on the surface thereof The casting defects and the inclusions deteriorate the mechanical strength of the magnesium alloy castings, and if they appear on the surface, they adversely affect the corrosion resistance and surface appearance of the castings.
In addition, although such forged magnesium alloys, or other hybrid crystalline alloy materials may have improved corrosion resistance, and provide equivalent mechanical strength to conventional metals in a lighter frame, thus far, there has been no attention paid to the elastic limit (a material""s ability to elastically deform prior to permanently deform) of such materials. Accordingly, cases for electronics products are generally formed with metals, which exhibit very poor elastic limits, reducing the ability of such cases to elastically store stress energy, and increasing the potential for permanent deformation of the electronics frame when subjected to a deforming stress.
Accordingly, a need exists for an electronics case which would improve the structural integrity and durability of a portable electronic device without increasing its weight or its manufacturing costs.
The current invention is directed to a metal frame for electronic hardware having improved physical mechanical properties including an elastic limit for the metal frame of at least about 1.5%, and preferably greater than about 2.0%; and preferably to highly processable metal frames wherein at least a portion of the frame is made of either a Zr/Ti or Fe-based bulk-solidifying amorphous alloys and bulk-solidifying amorphous alloy-composites.
In one embodiment, the bulk solidifying amorphous alloys are chosen from the family described by the molecular formula: (Zr, Ti)a(Ni, Cu, Fe)b(Be, Al, Si, B)c, where a is in the range of from 30 to 75, b is in the range of from 5 to 60, and c in the range of from 0 to 50 in atomic percentages. In another such embodiment, the alloys may accommodate substantial amounts of other transition metals up to 20% atomic, and more preferably metals such as Nb, Cr, V, Co.
In another embodiment, the alloy family is (Zr, Ti)a(Ni, Cu)b(Be)c, where a is in the range of from 40 to 75, b is in the range of from 5 to 50, and c in the range of from 5 to 50 in atomic percentages.
In another embodiment, composites of amorphous alloys are used to provide tailored stiffness, shock resistance and thermal conductivity properties to the frame. In such an embodiment, reinforcement materials for improved stiffness may be carbon fiber and preforms, or SIC fibers and preforms. In such an embodiment, the reinforcement materials preferably are from 20% up to 80% of the composite by volume. In a further embodiment, the direction and shape of the reinforcement materials may be tailored, for example, the materials may be aligned such that the desired properties (such as elastic modulus) are optimized in the direction parallel to length and width of the metal frame.
In another embodiment, the geometry of the frame may be tailored to provide a better combination of stiffness and flexibility. In such an embodiment, any desirable configuration may be utilized, such as honeycomb and wavy structures.
In another embodiment, the metal frame may further compromise other parts made of from different materials such as plastics, aluminum etc.
In another embodiment, the amorphous alloys are chosen to provide a hardness value of about 4 GPa or more, and preferably 5.5 GPa or more.
In another embodiment, the amorphous alloys are chosen to provide a yield strength of about 2 GPa or more.
In another embodiment, the amorphous alloys are chosen to provide a fracture toughness of about 10 ksi-sqrt(in) (sqrt:squre root) or more, and preferably 20 ksi sqrt(in) or more.
In another embodiment, the amorphous alloys are chosen to provide a density of at least 6.5 g/cc or less and preferably 4.5 g/cc or less.
In another embodiment, the amorphous alloys are chosen to have at least two properties one being the elastic limit, and the other chosen from the group of: hardness, yield strength, fracture toughness, and density within the above-referenced ranges.
In another embodiment, the amorphous alloys are chosen to have at least three properties one being the elastic limit, and the other two chosen from the group of: hardness, yield strength, fracture toughness, and density within the above-referenced ranges.
In another embodiment, the metal frame of the invention comprises of at least one part to form the metal frame assembly. In an embodiment in which the frame is made of at least two parts, one part may separately incorporate the electronic hardware and one part may incorporate the flat panel display. In such an embodiment, the parts of the metal frame may be joined by various techniques such as by bolting, clamping, adhesives, riveting or welding to secure its contents.
In another embodiment, the amorphous alloy frames are designed to provide structures, such as, ribs or support platforms, for the attenuation of shock and vibration for inner sensitive components such as hard drives.
In another embodiment, the amorphous alloys and composite frames are manufactured into sophisticated designs (such as incorporating more intricate features in shape-both functional, ergonomics and aesthetics), such as features of less than a micron in dimension.
In another embodiment, the invention is directed to a frame designed specifically for a portable electronic device, such as a PDA, a cellular phone, or a notebook computer.
In another embodiment, the invention is directed to a method of manufacturing an electronics device frame of an amorphous alloy. In such an embodiment, the amorphous alloy may be cast or molded around the materials glass transition temperature to duplicate details or provide more complex metal case designs.
In another embodiment, the metal frame is fabricated from sheets of amorphous alloys and composites by stamping and/or die forming operations. In such an embodiment, preferably the stamping and die-forming operations are performed around the glass transition temperatures. In another such embodiment, the metal frame may also be fabricated from sheets of amorphous alloys an composites by machining and cutting operations, such as, for example, water-jet, laser cutting, and Electro Discharge machining. The metal frame may also be fabricated by various forms by casting operations such as metal mold casting and melt infiltration process for amorphous alloy composites.
In another embodiment, the metal frame is machined, cut, stamped or die-formed with various slots and holes to provide improved cooling for the heat generated from the operation of electronic hardware, flat panel display. In such an embodiment, the metal frame may also be machined, cut, stamped or die-formed with various slots and holes to provide improved performance for internal sound system and speakers. Finally, in another such embodiment, the metal frame may be machined, cut, stamped or die-formed with various slots and holes to provide space for keyboard, mouse, track pad and other various accessories and other such attachments.